a1 Department of Biological and Environmental Science and Nanoscience Center, P.O. Box 35, 40014 University of Jyväskylä, Jyväskylä, Finland
Viruses are the dominant form of genetically reproducing entities on Earth. Yet, viruses are mostly neglected in the context of astrobiology due to their non-living nature. In this discussion it is considered whether viruses are likely to be transferred within bacterial endospores to other planetary bodies through lithopanspermia. Interestingly, it seems possible that ecosystems of panspermial origin might yield biospheres in which viruses are absent. The evolutionary pathway of life in these systems might differ significantly from the path observed on Earth. We hypothesize that the difference in the two potential ways for the emergence of life, those being panspermial or local origin, on any certain planet could be clarified by analyzing the diversity of virosphere on the planet. The use of viruses as putative biomarkers is also discussed and studied.
(Received September 17 2008)
(Revised November 11 2008)
(Revised March 27 2009)
(Accepted March 28 2009)
(Online publication May 12 2009)